Control method for an air conditioning heat pump system and air conditioning heat pump system

Abstract

To provide a control method for an air conditioning heat pump system that can improve the defrosting effect of the whole system.SOLUTION: A control method includes: acquiring evaporation capacity information on n outdoor units when an air conditioning pump system is in an alternate defrosting mode; sectioning, based upon the evaporation capacity information, the n outdoor units into m first outdoor units and k (n=m+k) second outdoor units whose sum of evaporation capacity parameters is equal to or less than the sum of evaporation capacity parameters of the m first outdoor units; controlling the m first outdoor units to operate in a heating mode and controlling the k second outdoor units to operate in a defrosting mode; and controlling the m first outdoor units to operate in the defrosting mode and controlling the k second outdoor units to operate in the heating mode after the k second outdoor units complete the defrosting.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and particularly to a control method for an air conditioning heat pump system and an air conditioning heat pump system.

Background Art

[0002] In related technologies, in order to ensure the comfort and reliability of air conditioners, when the frost layer is thick, the unit in the air conditioning heat pump system operates in the defrosting mode. In the defrosting mode, the outdoor unit of the air conditioner is in the condensing mode, and the indoor unit is in the cooling mode. However, when the frost layer is thick, the heat absorption capacity of the heat exchanger in the evaporator state is poor, which affects the defrosting effect of the heat exchanger in the condenser state, resulting in the problem that defrosting cannot be completed.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Embodiments of this application provide a control method for an air conditioning heat pump system and an air conditioning heat pump system to solve the problem of incomplete defrosting in an air conditioning heat pump system.

Means for Solving the Problems

[0004] To solve the above technical problems, this application is realized as follows.

[0005] According to a first aspect, an embodiment of the present application provides a method for controlling an air conditioning heat pump system. The air conditioning heat pump system includes an indoor unit and n (where n is an integer greater than 1) outdoor unit units. The control method includes obtaining evaporation capacity information for the n outdoor unit units, which includes n evaporation capacity parameters that correspond one-to-one to the n outdoor unit units, and which are used to represent the evaporation capacity of the corresponding outdoor unit unit during its operating process when the air conditioning heat pump system is in alternating defrosting mode; and, based on the evaporation capacity information, the n outdoor unit units are divided into m (where m is an integer greater than 0) first outdoor unit units, and the sum of the evaporation capacity parameters is the evaporation capacity of the m first outdoor unit units. This includes dividing the unit into k (where k is an integer greater than 0, and the sum of m and k is n) second outdoor unit units, the sum of which is less than or equal to the sum of the force parameters; controlling the m first outdoor unit units to operate in heating mode and the k second outdoor unit units to operate in defrost mode; and after defrosting of the k second outdoor unit units is completed, controlling the m first outdoor unit units to operate in defrost mode and the k second outdoor unit units to operate in heating mode.

[0006] In an optional embodiment, each of the first outdoor units includes one first compressor and one first heat exchanger, and each of the second outdoor units includes one second compressor and one second heat exchanger. When the m first outdoor units are operating in heating mode and the k second outdoor units are operating in defrosting mode, the first compressors are in operation and the second compressors are in non-operational state, the heat exchangers in the first outdoor units form evaporators in the air conditioning heat pump system, the heat exchangers in the second outdoor units form condensers in the air conditioning heat pump system, and in any of the second outdoor units, the input terminal of the second heat exchanger communicates with the output terminal of each first compressor and the output terminal of the second heat exchanger communicates with the input terminal of each first compressor. When the m first outdoor units operate in defrost mode and the k second outdoor units operate in heating mode, the first compressor is in a non-operating state and the second compressor is in an operating state, the heat exchanger in the first outdoor unit forms a condenser in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms an evaporator in the air conditioning heat pump system, and in any of the first outdoor units, the input terminal of the first heat exchanger communicates with the output terminal of each second compressor, and the output terminal of the first heat exchanger communicates with the input terminal of each second compressor.

[0007] As an optional embodiment, each of the first outdoor unit includes one first compressor and one first heat exchanger, and each of the second outdoor unit includes one second compressor and one second heat exchanger. When the m first outdoor unit units are operating in heating mode and the k second outdoor unit units are operating in defrosting mode, the first compressors are in operation, the second compressors are in operation, the heat exchangers in the first outdoor unit units form evaporators in the air conditioning heat pump system, the heat exchangers in the second outdoor unit units form condensers in the air conditioning heat pump system, and in any of the second outdoor unit units, the input terminal of the second compressor communicates with the output terminal of each first compressor, the output terminal of the second compressor communicates with the input terminal of the second heat exchanger, and the output terminal of the second heat exchanger communicates with the input terminal of each first compressor. When the m first outdoor units operate in defrost mode and the k second outdoor units operate in heating mode, the first compressor is in operation, the second compressor is in operation, the heat exchanger in the first outdoor unit forms a condenser in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms an evaporator in the air conditioning heat pump system, and in any of the first outdoor units, the input terminal of the first compressor communicates with the output terminal of each second compressor, the output terminal of the first compressor communicates with the input terminal of the first heat exchanger, and the output terminal of the first heat exchanger communicates with the input terminal of each second compressor.

[0008] In an optional embodiment, when the m first outdoor units operate in heating mode and the k second outdoor units operate in defrosting mode, the method further includes controlling the frequency of the first compressor based on the exhaust pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor. When the m first outdoor units operate in defrosting mode and the k second outdoor units operate in heating mode, the method further includes controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the exhaust pressure of the second compressor.

[0009] As an optional embodiment, controlling the frequency of the first compressor based on the exhaust pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor includes controlling the frequency of the first compressor to decrease when the exhaust pressure of the first compressor is greater than or equal to a first threshold, and controlling the frequency of the first compressor to increase when the exhaust pressure of the first compressor is less than the first threshold, and setting the frequency of the second compressor to a first frequency value which is a times the frequency of the first compressor when the compression ratio of the second compressor is greater than or equal to a second threshold, and setting the frequency of the second compressor to a second frequency value which is b (b>a) times the frequency of the first compressor when the compression ratio of the second compressor is less than the second threshold. Controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the exhaust pressure of the second compressor includes setting the frequency of the first compressor to a third frequency value which is a multiple of the frequency of the second compressor when the compression ratio of the first compressor is greater than or equal to the second threshold, setting the frequency of the first compressor to a fourth frequency value which is b multiple of the frequency of the second compressor when the compression ratio of the first compressor is less than the second threshold, and controlling the frequency of the second compressor to decrease when the exhaust pressure of the second compressor is greater than or equal to the first threshold, and controlling the frequency of the second compressor to increase when the exhaust pressure of the second compressor is less than the second threshold.

[0010] In an optional embodiment, the evaporation capacity parameter is determined based on the capacity parameter of the outdoor unit or the frost thickness value of the outdoor unit. Here, the evaporation capacity parameter and the capacity parameter show a positive correlation, and the evaporation capacity parameter and the frost thickness value show a negative correlation.

[0011] In one selectable embodiment, the frost thickness value and the power ratio of the outdoor unit, which is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, show a positive correlation.

[0012] As an optional embodiment, when the air conditioning heat pump system is in alternating defrost mode, before acquiring evaporation capacity information for the n outdoor unit units, the method further includes acquiring the power ratio of each of the n outdoor unit units, which is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, to obtain n power ratios; controlling the air conditioning heat pump system to transition to a normal defrost mode in which the heat exchangers in the n outdoor unit units form condensers and the heat exchangers in the indoor unit units form evaporators if at least one of the n power ratios is greater than or equal to a third threshold; and controlling the air conditioning heat pump system to transition to the alternating defrost mode if all of the n power ratios are less than the third threshold.

[0013] As an optional embodiment, when n is equal to 2, the m first outdoor unit units include the one outdoor unit with the largest evaporation capacity parameter value among the n outdoor unit units, and the k second outdoor unit units include the one outdoor unit with the smallest evaporation capacity parameter value among the n outdoor unit units. When n is equal to 3, the m first outdoor unit units include the two outdoor unit units with the smaller evaporation capacity parameter values ​​among the n outdoor unit units, and the k second outdoor unit units include the one outdoor unit with the largest evaporation capacity parameter value among the n outdoor unit units. When n is equal to 4, the m first outdoor unit units include the two outdoor unit units with the larger evaporation capacity parameter values ​​among the n outdoor unit units, and the k second outdoor unit units include the two outdoor unit units with the smaller evaporation capacity parameter values ​​among the n outdoor unit units.

[0014] According to a second aspect, an embodiment of the present application provides an air conditioning heat pump system comprising a controller, an indoor unit, a first transmission line, a second transmission line, and n (where n is an integer greater than 1) outdoor unit units, wherein the indoor unit and the n outdoor unit units are electrically connected to the controller. Each outdoor unit comprises a storage tank, a compressor, a heat exchanger, a first four-way valve, a second four-way valve, an electronic expansion valve, a first line, and a second line, and in each outdoor unit, the output end of the storage tank and the input end of the compressor are connected via a line, the output end of the compressor and the E end of the first four-way valve are connected via a line, the D end of the first four-way valve and the D end of the second four-way valve are connected via a line, and the C end of the second four-way valve and the input end of the heat exchanger are connected via a line. The output end of the heat exchanger is connected to the first end of the first conduit, the electronic expansion valve is provided in the first conduit, the second end of the first conduit forms the first external port of the outdoor unit, the S end of the second four-way valve and the C end of the first four-way valve are connected via a conduit, the S end of the first four-way valve and the input end of the storage tank are connected via a conduit, the E end of the second four-way valve is connected to the first end of the second conduit, and the second end of the second conduit forms the second external port of the outdoor unit. The first transmission conduit includes one input end connected to the output end of the indoor unit and n first connection ends connected in one-to-one correspondence to the n first external ports of the n outdoor unit units. The second transmission conduit includes one output terminal connected to the input terminal of the indoor unit and n second connection terminals connected in one-to-one correspondence to the n second external ports of the n outdoor unit units.

[0015] As a selectable embodiment, the controller controls the following when m of the n outdoor units are in heating mode and k of the n outdoor units are in defrosting mode: the D and E ends of the first four-way valve in the first outdoor unit are conductive, the S and C ends of the first four-way valve in the first outdoor unit are conductive, the D and E ends of the second four-way valve in the first outdoor unit are conductive, the S and C ends of the second four-way valve in the first outdoor unit are conductive, the D and C ends of the first four-way valve in the second outdoor unit are conductive, the S and E ends of the first four-way valve in the first outdoor unit are conductive, the D and C ends of the second four-way valve in the second outdoor unit are conductive, and the S and E ends of the second four-way valve in the second outdoor unit are conductive. Here, m and k are integers greater than 0, and the sum of m and k is n. The controller controls the first four-way valve in the first outdoor unit to conduct electricity when m of the n first outdoor unit units are in defrost mode and k of the n second outdoor unit units are in heating mode, so that the D and C ends of the first four-way valve in the first outdoor unit conduct electricity, the S and E ends of the first four-way valve in the first outdoor unit conduct electricity, the D and C ends of the second four-way valve in the first outdoor unit conduct electricity, the S and E ends of the second four-way valve in the first outdoor unit conduct electricity, the D and E ends of the first four-way valve in the second outdoor unit conduct electricity, the S and C ends of the first four-way valve in the first outdoor unit conduct electricity, the D and E ends of the second four-way valve in the second outdoor unit conduct electricity, and the S and C ends of the second four-way valve in the second outdoor unit conduct electricity. [Effects of the Invention]

[0016] In the embodiment of the present invention, when defrosting n outdoor units, the k second outdoor units, which have weaker evaporation capabilities, are defrosted first based on the m first outdoor units, which have stronger evaporation capabilities. This enhances the defrosting effect of the k second outdoor units, which are defrosted first. Once the defrosting of the k second outdoor units is complete, the evaporation capabilities of the k second outdoor units are significantly improved. Subsequently, the m first outdoor units are defrosted based on the k second outdoor units, resulting in a high defrosting effect for the m first outdoor units, which are defrosted next. This is advantageous for improving the overall defrosting effect of the air conditioning heat pump system. [Brief explanation of the drawing]

[0017] To more clearly illustrate the technical aspects of the embodiments of the present application, the drawings that may be used in the description of the embodiments of the present application are briefly described below. Clearly, the drawings in the following description are only a few embodiments of the present application, and those skilled in the art can obtain other drawings based on these without any creative effort.

[0018] [Figure 1] Figure 1 is a flowchart (part 1) of the control method for an air conditioning heat pump system provided by an embodiment of the present invention. [Figure 2] Figure 2 is a schematic diagram (part 1) of the configuration of the air conditioning heat pump system provided by the embodiment of the present invention. [Figure 3] Figure 3 is a schematic diagram (part 2) of the configuration of the air conditioning heat pump system provided by the embodiment of the present invention. [Figure 4] Figure 4 is a flowchart showing how to adjust the compressor frequency F2 of ODU2 during the defrosting process of ODU1 in an embodiment of the present invention. [Figure 5] Figure 5 is a flowchart showing how to adjust the compressor frequency F2 of ODU2 during the defrosting process of ODU2 in an embodiment of the present invention. [Figure 6] Figure 6 is a flowchart (part 2) of the control method for the air conditioning heat pump system provided by the embodiment of the present invention. [Figure 7]FIG. 7 is a flowchart of defrost mode determination in an embodiment of the present application. [Figure 8] FIG. 8 is a schematic configuration diagram of the air-conditioning heat pump system provided by the embodiment of the present application, part 3. [Figure 9] FIG. 9 is a flowchart of the control method of the air-conditioning heat pump system provided by the embodiment of the present application, part 3. [Figure 10] FIG. 10 is a flowchart of the control method of the air-conditioning heat pump system provided by the embodiment of the present application, part 4. [Figure 11] FIG. 11 is a flowchart of the control method of the air-conditioning heat pump system provided by the embodiment of the present application, part 5. [Figure 12] FIG. 12 is a schematic configuration diagram of the air-conditioning heat pump system provided by the embodiment of the present application, part 4. [Figure 13] FIG. 13 is a flowchart of the control method of the air-conditioning heat pump system provided by the embodiment of the present application, part 6. [Figure 14] FIG. 14 is a schematic configuration diagram of the air-conditioning heat pump system provided by the embodiment of the present application, part 5. [Figure 15] FIG. 15 is a flowchart of the control method of the air-conditioning heat pump system provided by the embodiment of the present application, part 7. [Figure 16] FIG. 16 is a flowchart of the control method of the air-conditioning heat pump system provided by the embodiment of the present application, part 8. [Figure 17] FIG. 17 is a flowchart of the control method of the air-conditioning heat pump system provided by the embodiment of the present application, part 9. [Figure 18] FIG. 18 is a flowchart of the control method of the air-conditioning heat pump system provided by the embodiment of the present application, part 10.

BEST MODE FOR CARRYING OUT THE INVENTION

[0019] Hereinafter, the technical aspects of the embodiments of the present application will be clearly and completely described in relation to the accompanying drawings. Clearly, the embodiments described are some, but not all, embodiments of the present application. All other embodiments obtained by a person skilled in the art without any creative work based on the embodiments of the present application are within the scope of protection of the present application.

[0020] Refer to Figure 1. Figure 1 is a flowchart of a control method for an air conditioning heat pump system provided by an embodiment of the present invention. The air conditioning heat pump system includes an indoor unit and n outdoor unit units, where n is an integer greater than 1. The control method includes the following steps. In step 101, if the air conditioning heat pump system is in alternating defrost mode, evaporation capacity information for the n outdoor unit is obtained. The evaporation capacity information includes n evaporation capacity parameters that correspond one-to-one with the n outdoor unit. The evaporation capacity parameters are used to represent the evaporation capacity of the corresponding outdoor unit during operation. In step 102, based on the evaporation capacity information, the n outdoor unit units are divided into m (where m is an integer greater than 0) first outdoor unit units and k (where k is an integer greater than 0, and the sum of m and k is n) second outdoor unit units, the sum of which of the evaporation capacity parameters is less than or equal to the sum of the evaporation capacity parameters of the m first outdoor unit units. In step 103, the m first outdoor units are controlled to operate in heating mode, and the k second outdoor units are controlled to operate in defrost mode. In step 104, after the defrosting of the k second outdoor units is completed, the m first outdoor units are controlled to operate in defrost mode, and the k second outdoor units are controlled to operate in heating mode.

[0021] Here, the air conditioning heat pump system may be various types of multi-online air conditioning heat pump systems. The air conditioning heat pump system may further include controllers electrically connected to the indoor unit and n outdoor unit units in order to implement various processes of the control method. The control method is used to implement the defrosting process of the air conditioning heat pump system. The value of n is set according to the actual requirements. For example, n may be 2, 3, 4, etc.

[0022] In some embodiments of the present application, the air conditioning heat pump system includes a controller, an indoor unit, a first transmission line, a second transmission line, and n (where n is an integer greater than 1) outdoor unit units, the indoor unit and the n outdoor unit units are each electrically connected to the controller. Each outdoor unit includes a storage tank, a compressor, a heat exchanger, a first four-way valve, a second four-way valve, an electronic expansion valve, a first line, and a second line, and in each outdoor unit, the output end of the storage tank and the input end of the compressor are connected via a line, the output end of the compressor and the E end of the first four-way valve are connected via a line, the D end of the first four-way valve and the D end of the second four-way valve are connected via a line, and the C end of the second four-way valve and the input end of the heat exchanger are connected via a line. The output end of the heat exchanger is connected to the first end of the first conduit, the electronic expansion valve is provided in the first conduit, the second end of the first conduit forms the first external port of the outdoor unit, the S end of the second four-way valve and the C end of the first four-way valve are connected via a conduit, the S end of the first four-way valve and the input end of the storage tank are connected via a conduit, the E end of the second four-way valve is connected to the first end of the second conduit, and the second end of the second conduit forms the second external port of the outdoor unit. The first transmission conduit includes one input end connected to the output end of the indoor unit and n first connection ends connected in one-to-one correspondence to the n first external ports of the n outdoor unit units. The second transmission conduit includes one output end connected to the input end of the indoor unit and n second connection ends connected in one-to-one correspondence to the n second external ports of the n outdoor unit units. For example, refer to Figure 2. Figure 2 is a schematic diagram of the configuration of the air conditioning heat pump system when n is equal to 2. Here, in Figure 2, ODU1 is the first outdoor unit, ODU2 is the second outdoor unit, IDU1 is the first indoor unit, IDU2 is the second indoor unit, IDU3 is the third indoor unit, and IDU4 is the fourth indoor unit, where IDU1, IDU2, IDU3, and IDU4 together form an indoor unit.CSGL1 represents the first transmission conduit, CSGL2 represents the second transmission conduit, 1#Acc represents the storage tank in ODU1, 1#YSJ represents the compressor in ODU1, 1#HEX represents the heat exchanger in ODU1, 1#STF1 represents the first four-way valve in ODU1, 1#STF2 represents the second four-way valve in ODU1, 1#EVO represents the electronic expansion valve in ODU1, 1#GL1 represents the first conduit in ODU1, and 1#GL2 represents the second conduit in ODU1. 2#Acc represents the storage tank in ODU2, 2#YSJ represents the compressor in ODU2, 2#HEX represents the heat exchanger in ODU2, 2#STF1 represents the first four-way valve in ODU2, 2#STF2 represents the second four-way valve in ODU2, 2#EVO represents the electronic expansion valve in ODU2, 2#GL1 represents the first pipeline in ODU2, and 2#GL2 represents the second pipeline in ODU2.

[0023] The number of indoor units in the above indoor unit unit may be one or more. If the indoor unit unit includes at least two indoor units, these at least two indoor units are connected in parallel between the input end of the first transmission conduit and the output end of the second transmission conduit. For example, referring to Figure 2, the indoor unit unit includes four indoor units connected in parallel.

[0024] It is understood that, among the n outdoor unit units, each outdoor unit is connected in series with the indoor unit via the first and second transmission lines to form n heat exchange circuits. In this way, each outdoor unit forms a complete air conditioning system with the indoor unit, enabling cooling or heating of the environment in which the indoor unit is located. Alternatively, two or more outdoor unit units may operate together to improve the cooling or heating capacity of the air conditioning heat pump system, thereby jointly cooling or heating the environment in which the indoor unit is located based on two or more outdoor unit units that are in operation. When two or more outdoor unit units jointly cool or heat the environment in which the indoor unit is located, the two or more outdoor unit units that are in operation are in parallel, and each outdoor unit is connected in series with the indoor unit. In this manner, the refrigerant output from two or more operating outdoor units merges in the second transmission line shown in Figure 2, the merged refrigerant enters the indoor unit, flows through the indoor unit again into the first transmission line, and is returned to the two or more operating outdoor units via the first transmission line.

[0025] When the m first outdoor units operate in heating mode and the k second outdoor units operate in defrosting mode, the k second outdoor units can be made equivalent to a part of the indoor unit. In this case, each first outdoor unit can be connected in series with any of the second outdoor units via a first and second transmission line to form a complete circuit. At the same time, each first outdoor unit can be connected in series with an indoor unit via a first and second transmission line to form a complete circuit, which corresponds to a state in which the second outdoor units and indoor units are connected in parallel. In this way, by controlling the first outdoor units to heating mode, the second outdoor units can be heated so that the frost layer on the surface of the second outdoor units melts, thereby achieving defrosting of the second outdoor units.

[0026] For example, referring to Figure 2, in some embodiments of the present application, the air conditioning heat pump system includes two outdoor unit units, ODU1 and ODU2, and the indoor unit unit includes four indoor units, IDU1, IDU2, IDU3, and IDU4. The refrigerant flow shown in Figure 2 is a schematic diagram of the defrosting process of ODU2 based on ODU1, i.e., ODU1 is in heating mode and ODU2 is in defrosting mode. In this case, n is equal to 2, ODU1 forms the first outdoor unit, and ODU2 forms the second outdoor unit. As shown in Figure 2, a low-temperature, low-pressure gaseous refrigerant is stored in the storage tank of ODU1, and the compressor in ODU1 consumes electricity to draw the refrigerant from the storage tank and converts the refrigerant into a high-temperature, high-pressure gas. The high-temperature, high-pressure refrigerant flows sequentially through the E end of the first four-way valve in ODU1, the D end of the first four-way valve in ODU1, the D end of the second four-way valve in ODU1, the E end of the second four-way valve in ODU1, and the second pipeline in ODU1 before entering the second transmission pipeline. A portion of the high-temperature, high-pressure refrigerant that enters the second transmission pipeline enters the indoor unit, and another portion enters the second pipeline in ODU2. The high-temperature, high-pressure refrigerant that enters the second pipeline flows sequentially through the E end of the second four-way valve in ODU2, the S end of the second four-way valve in ODU2, the C end of the first four-way valve in ODU2, the C end of the first four-way valve in ODU2, the D end of the first four-way valve in ODU2, the D end of the second four-way valve in ODU2, and the C end of the second four-way valve in ODU2 before entering the heat exchanger in ODU2. At this time, the high-temperature, high-pressure gaseous refrigerant is condensed into a low-temperature, high-pressure liquid refrigerant in the heat exchanger in ODU2, which serves as the condenser. During condensation, a large amount of heat is released from the refrigerant, heating the heat exchanger in ODU2 and defrosting it. The low-temperature, high-pressure refrigerant that has flowed out of the heat exchanger in ODU2 flows through the first pipeline in ODU2 and enters the first transmission pipeline. Furthermore, during the process of flowing through the first pipeline in ODU2, an electronic expansion valve located in the first pipeline in ODU2 can reduce the pressure of the low-temperature, high-pressure liquid refrigerant, converting it into a low-temperature, low-pressure liquid refrigerant. Correspondingly, other high-temperature, high-pressure refrigerants flowing through the indoor unit also condense into liquid and enter the first transmission pipeline. As a result, the refrigerants that have entered the first transmission pipeline from ODU2 and the indoor unit unit merge in the first transmission pipeline and then flow through the first pipeline of ODU1 and enter the heat exchanger of ODU1.The low-temperature, low-pressure liquid refrigerant entering the heat exchanger of ODU1 absorbs heat from outside the heat exchanger of ODU1 and evaporates into a low-temperature, low-pressure gaseous refrigerant. In this process, the heat exchanger of ODU1 functions as an evaporator, and the other low-temperature, low-pressure refrigerant flows sequentially through the C end of the second four-way valve in ODU1, the S end of the second four-way valve in ODU1, the C end of the first four-way valve in ODU1, and the S end of the first four-way valve in ODU1, and enters the storage tank in ODU1. This realizes the defrosting process of ODU2.

[0027] Once the defrosting process for ODU2 is complete, the state of the two four-way valves in ODU1 is switched to the corresponding state of the two four-way valves in ODU2 in Figure 2, and then the state of the two four-way valves in ODU2 is switched to the corresponding state of the two four-way valves in ODU1 in Figure 2. Subsequently, ODU2 is controlled to operate in heating mode and ODU1 is controlled to operate in defrosting mode to defrost ODU1. This defrosting process is the same as in the above embodiment, and to avoid repetition, it will not be described further here.

[0028] The stronger the evaporation capacity, which is the heat absorption capacity of the heat exchanger described above, the stronger the corresponding heat absorption capacity becomes, and the better the defrosting effect.

[0029] In this embodiment, when defrosting n outdoor units, the defrosting effect of the k second outdoor units, which have weaker evaporation capabilities, is enhanced by defrosting the k second outdoor units, which are defrosted first, based on the m first outdoor units, which have stronger evaporation capabilities. Once the defrosting of the k second outdoor units is complete, the evaporation capabilities of the k second outdoor units are significantly improved. Subsequently, the defrosting of the m first outdoor units is performed based on the k second outdoor units, so the defrosting effect of the m first outdoor units, which are defrosted next, is also high, which is advantageous for improving the overall defrosting effect of the air conditioning heat pump system.

[0030] In an optional embodiment, each of the first outdoor units includes one first compressor and one first heat exchanger, and each of the second outdoor units includes one second compressor and one second heat exchanger. When the m first outdoor units are operating in heating mode and the k second outdoor units are operating in defrosting mode, the first compressors are in operation and the second compressors are in non-operational state, the heat exchangers in the first outdoor units form evaporators in the air conditioning heat pump system, the heat exchangers in the second outdoor units form condensers in the air conditioning heat pump system, and in any of the second outdoor units, the input terminal of the second heat exchanger communicates with the output terminal of each first compressor and the output terminal of the second heat exchanger communicates with the input terminal of each first compressor. When the m first outdoor units operate in defrost mode and the k second outdoor units operate in heating mode, the first compressor is in a non-operating state and the second compressor is in an operating state, the heat exchanger in the first outdoor unit forms a condenser in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms an evaporator in the air conditioning heat pump system, and in any of the first outdoor units, the input terminal of the first heat exchanger communicates with the output terminal of each second compressor, and the output terminal of the first heat exchanger communicates with the input terminal of each second compressor.

[0031] In related technologies, during the process of defrosting the second outdoor unit based on the first outdoor unit, both the compressor in the first outdoor unit and the compressor in the second outdoor unit are operating, and the refrigerant discharged from the compressor in the first outdoor unit may directly enter the intake side of the compressor in the second outdoor unit. This can lead to problems such as the compression ratio of the compressor in the outdoor unit in defrost mode being too low, or the exhaust pressure of the compressor in the outdoor unit in heating mode being too low.

[0032] Refer to Figure 2. In the embodiment shown in Figure 2, the heat exchanger in ODU1 forms the first heat exchanger, the compressor in ODU1 forms the first compressor, the heat exchanger in ODU2 forms the second heat exchanger, and the compressor in ODU2 forms the second compressor.

[0033] In this embodiment, by adding one four-way valve to each outdoor unit, that is, by including two four-way valves in each outdoor unit to change the flow of refrigerant, the refrigerant that enters the second outdoor unit does not flow through the compressor in the second outdoor unit but enters directly into the heat exchanger of the second outdoor unit and condenses, and by maintaining the closed state of the compressor in the second outdoor unit, problems such as the compression ratio of the compressor in the outdoor unit in defrost mode being too low, or the exhaust pressure of the compressor in the outdoor unit in heating mode being too low, are avoided.

[0034] As an optional embodiment, each of the first outdoor unit includes one first compressor and one first heat exchanger, and each of the second outdoor unit includes one second compressor and one second heat exchanger. When the m first outdoor unit units are operating in heating mode and the k second outdoor unit units are operating in defrosting mode, the first compressors are in operation, the second compressors are in operation, the heat exchangers in the first outdoor unit units form evaporators in the air conditioning heat pump system, the heat exchangers in the second outdoor unit units form condensers in the air conditioning heat pump system, and in any of the second outdoor unit units, the input terminal of the second compressor communicates with the output terminal of each first compressor, the output terminal of the second compressor communicates with the input terminal of the second heat exchanger, and the output terminal of the second heat exchanger communicates with the input terminal of each first compressor. When the m first outdoor units operate in defrost mode and the k second outdoor units operate in heating mode, the first compressor is in operation, the second compressor is in operation, the heat exchanger in the first outdoor unit forms a condenser in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms an evaporator in the air conditioning heat pump system, and in any of the first outdoor units, the input terminal of the first compressor communicates with the output terminal of each second compressor, the output terminal of the first compressor communicates with the input terminal of the first heat exchanger, and the output terminal of the first heat exchanger communicates with the input terminal of each second compressor.

[0035] Figure 3 is a schematic diagram of the configuration of an air conditioning heat pump system provided by another embodiment of the present invention. This air conditioning heat pump system differs from the air conditioning heat pump system shown in Figure 2 in the following respects. Specifically, the air conditioning heat pump system in Figure 3 has one less four-way valve in each outdoor unit, meaning that each outdoor unit contains only one four-way valve, and accordingly the connection relationships are adaptively adjusted, and both the compressor in ODU1 and the compressor in ODU2 are operating during the defrosting process. Figure 3 is a flowchart of the defrosting process of ODU2 when ODU1 is in heating mode and ODU2 is in defrosting mode. As shown in Figure 3, a low-temperature, low-pressure gaseous refrigerant is stored in the storage tank of ODU1, and the compressor in ODU1 consumes electricity to draw the refrigerant from the storage tank and converts the refrigerant into a high-temperature, high-pressure gas. The high-temperature, high-pressure refrigerant flows sequentially through the E end of the four-way valve in ODU1, the D end of the four-way valve in ODU1, and the second pipeline in ODU1 before entering the second transmission pipeline. Since the second transmission pipeline is in communication with the intake side of the compressor in ODU2, the suction action of the compressor in ODU2 causes the high-temperature, high-pressure refrigerant that entered the second transmission pipeline to flow through the second pipeline in ODU2, the E end of the four-way valve in ODU2, the S end of the four-way valve in ODU2, and the storage tank in ODU2 before entering the compressor in ODU2. The compressor in ODU2 outputs the high-temperature, high-pressure gaseous refrigerant to the heat exchanger in ODU2. At this time, the high-temperature, high-pressure gaseous refrigerant is condensed into a low-temperature, high-pressure liquid refrigerant in the heat exchanger in ODU2, which acts as a condenser. During condensation, a large amount of heat is released from the refrigerant, heating the heat exchanger in ODU2 and defrosting the heat exchanger in ODU2. The low-temperature, high-pressure refrigerant that flows out of the heat exchanger in ODU2 flows through the first pipeline in ODU2 and enters the first transmission pipeline. During the process of flowing through the first pipeline in ODU2, the electronic expansion valve located in the first pipeline in ODU2 reduces the pressure of the low-temperature, high-pressure liquid refrigerant, converting it into low-temperature, low-pressure liquid refrigerant. After entering the first transmission pipeline, the low-temperature, low-pressure liquid refrigerant flows to the heat exchanger in ODU1, and then returns to the storage tank in ODU1 via the heat exchanger.In Figure 3, ODU1 represents the first outdoor unit, ODU2 represents the second outdoor unit, IDU1 represents the first indoor unit, IDU2 represents the second indoor unit, IDU3 represents the third indoor unit, and IDU4 represents the fourth indoor unit, where IDU1, IDU2, IDU3, and IDU4 together form an indoor unit. CSGL1 represents the first transmission conduit, CSGL2 represents the second transmission conduit, 1#Acc represents the storage tank in ODU1, 1#YSJ represents the compressor in ODU1, 1#HEX represents the heat exchanger in ODU1, 1#STF represents the four-way valve in ODU1, 1#EVO represents the electronic expansion valve in ODU1, 1#GL1 represents the first conduit in ODU1, and 1#GL2 represents the second conduit in ODU1. 2#Acc represents the storage tank in ODU2, 2#YSJ represents the compressor in ODU2, 2#HEX represents the heat exchanger in ODU2, 2#STF represents the four-way valve in ODU2, 2#EVO represents the electronic expansion valve in ODU2, 2#GL1 represents the first pipeline in ODU2, and 2#GL2 represents the second pipeline in ODU2.

[0036] In an optional embodiment, when the m first outdoor units operate in heating mode and the k second outdoor units operate in defrosting mode, the method further includes controlling the frequency of the first compressor based on the exhaust pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor. The compression ratio ε2 of the second compressor is Pd2 / Ps2, where Pd2 is the exhaust pressure of the second compressor and Ps2 is the intake pressure of the second compressor. When the m first outdoor units operate in defrosting mode and the k second outdoor units operate in heating mode, the method further includes controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the exhaust pressure of the second compressor. The compression ratio ε1 of the first compressor is Pd1 / Ps1, where Pd1 is the exhaust pressure of the first compressor and Ps1 is the intake pressure of the first compressor.

[0037] In the embodiment shown in Figure 3, since both the first and second compressors are operating, there are problems such as the compression ratio of the compressor in the outdoor unit in defrost mode being too low, and the exhaust pressure of the compressor in the outdoor unit in heating mode being too low.

[0038] Here, controlling the frequency of the first compressor based on the exhaust pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor includes controlling the frequency of the first compressor to decrease when the exhaust pressure of the first compressor is greater than or equal to a first threshold, and controlling the frequency of the first compressor to increase when the exhaust pressure of the first compressor is less than the first threshold, and setting the frequency of the second compressor to a first frequency value which is a (a>0) times the frequency of the first compressor when the compression ratio of the second compressor is greater than or equal to a second threshold, and setting the frequency of the second compressor to a second frequency value which is b (b>a) times the frequency of the first compressor when the compression ratio of the second compressor is less than the second threshold.

[0039] Specifically, the first threshold is set according to actual needs. When the exhaust pressure of the first compressor is equal to or greater than the first threshold, the frequency of the first compressor is controlled to decrease, and when the exhaust pressure of the first compressor is less than the first threshold, the frequency of the first compressor is controlled to increase. This ensures that the exhaust pressure of the first compressor in heating mode is always near the first threshold, thereby avoiding the problem of the exhaust pressure of the first compressor being too low.

[0040] Correspondingly, the second threshold is also set according to the actual needs. When the frequency of the second compressor drops below the second threshold, the frequency of the second compressor is switched from the first frequency value to the second frequency value, that is, the frequency value of the second compressor is increased, which increases Pd2 and Pd2 / Ps2 accordingly, thus avoiding the problem of the compression ratio ε2 of the second compressor being too low.

[0041] Controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the exhaust pressure of the second compressor includes setting the frequency of the first compressor to a third frequency value which is a multiple of the frequency of the second compressor when the compression ratio of the first compressor is greater than or equal to the second threshold, setting the frequency of the first compressor to a fourth frequency value which is b multiple of the frequency of the second compressor when the compression ratio of the first compressor is less than the second threshold, and controlling the frequency of the second compressor to decrease when the exhaust pressure of the second compressor is greater than or equal to the first threshold, and controlling the frequency of the second compressor to increase when the exhaust pressure of the second compressor is less than the second threshold.

[0042] Figure 4 is a flowchart for adjusting the compressor frequency F2 of ODU2 during the defrosting process of ODU1. Here, Pd2 is the exhaust pressure of the second compressor in ODU2, and G is the first threshold. Figure 5 is a flowchart for adjusting the compressor frequency F2 in ODU2 during the defrosting process of ODU2. Here, Pd2 is the exhaust pressure of the second compressor in ODU2, Ps2 is the intake pressure of the second compressor in ODU2, ε2 is the compression ratio of the second compressor, and H is the second threshold. Correspondingly, the frequency of ODU1 is adjusted in a similar manner.

[0043] Refer to the table below. This table is a comparison table of compressor operating parameters in the defrosting process of the technical aspects of the present invention and the technical aspects of related technologies. As is clear from the table, compared to related technologies, the technical aspects of the present invention can effectively increase the compression ratio of the compressor in the outdoor unit in defrosting mode and effectively increase the exhaust pressure of the compressor in the outdoor unit in heating mode.

[0044] [Table 1]

[0045] In this embodiment, when the m first outdoor unit units operate in heating mode and the k second outdoor unit units operate in defrost mode, the frequency of the first compressor is controlled based on the compression ratio of the first compressor and the frequency of the second compressor is controlled based on the exhaust pressure of the second compressor, thereby avoiding problems that occur during the defrosting process of the second outdoor unit units, such as the compression ratio of the compressor in the outdoor unit unit in defrost mode being too low or the exhaust pressure of the compressor in the outdoor unit unit in heating mode being too low. Correspondingly, when the m first outdoor unit units operate in defrost mode and the k second outdoor unit units operate in heating mode, the frequency of the first compressor is controlled based on the compression ratio of the first compressor and the frequency of the second compressor is controlled based on the exhaust pressure of the second compressor, thereby avoiding problems that occur during the defrosting process of the first outdoor unit units, such as the compression ratio of the compressor in the outdoor unit unit in defrost mode being too low or the exhaust pressure of the compressor in the outdoor unit unit in heating mode being too low.

[0046] In a selectable embodiment, the evaporation capacity parameter is determined based on the capacity parameter of the outdoor unit, the frost thickness value of the outdoor unit, or whether the outdoor unit satisfies the defrosting conditions. Here, the evaporation capacity parameter and the capacity parameter show a positive correlation, and the evaporation capacity parameter and the frost thickness value show a negative correlation.

[0047] Here, the capacity parameter of the outdoor unit, which is the number of outdoor units, can be, for example, 1, 2, 3, etc. The frost thickness value is the frost thickness on the surface of the outdoor unit. The frost thickness value and the power ratio of the outdoor unit show a positive correlation. Since the power ratio is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, the frost thickness value of the outdoor unit can be represented by the power ratio of the outdoor unit. The peak power may be the peak power during the previous startup of the fan, and the operating power may be the real-time power of the fan. In the related art, usually, when the thickness of the frost layer of the outdoor unit is greater than or equal to a specific threshold, it is determined that the outdoor unit satisfies the defrosting condition. When the thickness of the frost layer of the outdoor unit is less than the specific threshold, it is determined that the outdoor unit does not satisfy the defrosting condition. Therefore, by setting the evaporation capacity parameter of the outdoor unit that satisfies the defrosting condition to 1 and the evaporation capacity parameter of the outdoor unit that does not satisfy the defrosting condition to 0, the evaporation capacity parameter can be determined according to whether the outdoor unit satisfies the defrosting condition.

[0048] Referring to FIG. 9, in some embodiments of the present application, the air-conditioning heat pump system includes two outdoor units, ODU1 and ODU2. In the alternating defrosting mode, the capacity parameter C1 of ODU1 and the capacity parameter C2 of ODU2 are obtained. When C1≥C2, first, ODU2 is defrosted. After the defrosting of ODU2 is completed, ODU1 is further defrosted. When C1<C2, first, ODU1 is defrosted. After the defrosting of ODU1 is completed, ODU2 is further defrosted.

[0049] In some embodiments of the present application, the air-conditioning heat pump system includes two outdoor units, ODU1 and ODU2. In the alternating defrosting mode, the evaporation capacity parameters of ODU1 and ODU2 are obtained according to whether the defrosting condition is satisfied. When the evaporation capacity parameter of ODU1 is 0 and the evaporation capacity parameter of ODU2 is 1, first, ODU1 is defrosted. After the defrosting of ODU1 is completed, ODU2 is further defrosted.

[0050] In other embodiments of the present application, the air-conditioning heat pump system includes four outdoor unit units, ODU1, ODU2, ODU3, and ODU4. In the alternate defrosting mode, according to whether the defrosting conditions are met, the evaporation capacity parameters of ODU1, ODU2, ODU3, and ODU4 are obtained. When the evaporation capacity parameters of both ODU1 and ODU2 are 0 and the evaporation capacity parameters of both ODU3 and ODU4 are 1, first ODU1 and ODU2 are defrosted. After the defrosting of ODU1 and ODU2 is completed, ODU3 and ODU4 are further defrosted.

[0051] Refer to FIG. 10. In some embodiments of the present application, the air-conditioning heat pump system includes two outdoor unit units, ODU1 and ODU2. In the alternate defrosting mode, the power ratio λ1 of ODU1 and the power ratio λ2 of ODU2 are obtained. When λ1 ≥ λ2, first ODU2 is defrosted. After the defrosting of ODU2 is completed, ODU1 is further defrosted. When λ1 < λ2, first ODU1 is defrosted. After the defrosting of ODU1 is completed, ODU2 is further defrosted.

[0052] Also, refer to FIG. 11. In some embodiments of the present application, it may be set that defrosting is not performed when the power ratio of the outdoor unit unit is below the fourth threshold value C, and defrosting is performed when the power ratio of the outdoor unit unit is greater than C.

[0053] Refer to FIG. 6. In some embodiments of the present application, the evaporation capacity parameter may simultaneously include the capacity parameter of the outdoor unit unit and the frosting thickness value of the outdoor unit unit. When C1 ≥ C2, if λ1 ≤ λ2, first ODU2 is defrosted. After the defrosting of ODU2 is completed, ODU1 is further defrosted. When C1 < C2, first ODU1 is defrosted. After the defrosting of ODU1 is completed, ODU2 is further defrosted. When λ1 < λ2, first ODU1 is defrosted. After the defrosting of ODU1 is completed, ODU2 is further defrosted.

[0054] As an optional embodiment, when the air conditioning heat pump system is in alternating defrost mode, before acquiring evaporation capacity information for the n outdoor unit units, the method further includes acquiring the power ratio of each of the n outdoor unit units, which is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, to obtain n power ratios; controlling the air conditioning heat pump system to transition to a normal defrost mode in which the heat exchangers in the n outdoor unit units form condensers and the heat exchangers in the indoor unit units form evaporators if at least one of the n power ratios is greater than or equal to a third threshold; and controlling the air conditioning heat pump system to transition to the alternating defrost mode if all of the n power ratios are less than the third threshold.

[0055] Referring to Figure 7, in some embodiments of the present invention, the air conditioning heat pump system includes two outdoor unit units, ODU1 and ODU2, and the defrost mode determination process includes the following steps. Obtain the peak power P1 from the previous defrosting start for ODU1 and the peak power P2 from the previous defrosting start for ODU2. During heating operation, the maximum fan power Pa of ODU1 and the maximum fan power Pb of ODU2 are recorded every t hours. Calculate the power ratio of the two outdoor unit units. λ1 = Pa / P1, λ2 = Pb / P2. When a defrosting signal is received, the relative magnitudes of judgments λ1, λ2, and the third threshold E are determined. If λ1 ≥ E or λ2 ≥ E, the system switches to normal defrost mode; otherwise, it switches to alternating defrost mode.

[0056] Here, if the power ratio of the outdoor unit is greater than or equal to the third threshold, it indicates that the frost thickness on the surface of the outdoor unit is large, and in this case, there is a problem that defrosting cannot be completed in alternating defrosting mode. Based on this, if the power ratio of at least one outdoor unit is greater than or equal to the third threshold, defrosting is performed using the normal defrosting mode. In normal defrosting mode, all outdoor unit is in defrosting mode and the compressors in all outdoor unit are operating, which is advantageous for improving the defrosting effect. In any case, if all of the n power ratios are less than the third threshold, controlling the air conditioning heat pump system to switch to the alternating defrosting mode will guarantee the defrosting effect and shorten the time required for the defrosting operation.

[0057] In the embodiment shown in Figure 8, when the air conditioning heat pump system is in heating mode, the outdoor unit heat exchangers of ODU1 and ODU2 are in the evaporator state, with low temperature and pressure, while all indoor units are in the condenser state, with high temperature and pressure. At this time, the compressors of outdoor units ODU1 and ODU2 are in parallel.

[0058] In the embodiment shown in Figure 8, when the air conditioning heat pump system is in normal defrost mode, both the outdoor unit heat exchangers of ODU1 and ODU2 switch to the condenser state, and all indoor units are in the evaporator state, resulting in low temperature and pressure.

[0059] In the embodiment shown in Figure 8, when the air conditioning heat pump system is in alternating defrost mode, ODU1 and ODU2 alternately defrost, maintaining one heat exchanger of the outdoor unit in an evaporator state. In this case, the indoor unit is in a medium pressure state and the temperature is high. If the frost layer on the heat exchangers of ODU1 and ODU2 is relatively thick, the evaporation capacity of the heat exchangers is poor, and alternating defrosting often fails to defrost properly, affecting the comfort and reliability of subsequent operation of the air conditioner. At this time, the compressors of outdoor units ODU1 and ODU2 are in series. Because the refrigerant on the exhaust side of the outdoor unit compressor that performs heating directly enters the intake side of the outdoor unit compressor that performs defrosting, the compressor of the outdoor unit that performs defrosting is very likely to have a problem of having too low a compression ratio, and at the same time, the compressor of the outdoor unit that performs heating is also very likely to have a problem of having too low an exhaust pressure.

[0060] Here, if ODU1 is in heating mode and ODU2 is in defrosting mode, the frequency of the compressor of ODU1 is controlled by the exhaust pressure of the compressor of ODU1, and the frequency of the compressor of ODU2 is controlled by the compression ratio of the compressor of ODU2. If ODU1 is in defrosting mode and ODU2 is in heating mode, the frequency of the compressor of ODU2 is controlled by the exhaust pressure of the compressor of ODU2, and the frequency of the compressor of ODU1 is controlled by the compression ratio of the compressor of ODU1.

[0061] Frost formation on the unit leads to an increase in fan power at the same rotation speed. First, the frost thickness on the unit is determined by the power increase ratio, and then a decision is made as to whether or not to switch to alternating defrosting, thereby ensuring that defrosting is done thoroughly. At the same time, the priority of defrosting the units is determined, and outdoor units with low evaporation capacity are defrosted first, ensuring that outdoor units with high evaporation capacity have strong evaporation capacity and that outdoor units with low evaporation capacity are thoroughly defrosted. Once the outdoor units with low evaporation capacity are thoroughly defrosted, their evaporation capacity increases, and then outdoor units with high evaporation capacity are defrosted, ensuring that all outdoor units are thoroughly defrosted.

[0062] As an optional embodiment, when n is equal to 2, the m first outdoor unit units include the one outdoor unit with the largest evaporation capacity parameter value among the n outdoor unit units, and the k second outdoor unit units include the one outdoor unit with the smallest evaporation capacity parameter value among the n outdoor unit units. When n is equal to 3, the m first outdoor unit units include the two outdoor unit units with the smaller evaporation capacity parameter values ​​among the n outdoor unit units, and the k second outdoor unit units include the one outdoor unit with the largest evaporation capacity parameter value among the n outdoor unit units. When n is equal to 4, the m first outdoor unit units include the two outdoor unit units with the larger evaporation capacity parameter values ​​among the n outdoor unit units, and the k second outdoor unit units include the two outdoor unit units with the smaller evaporation capacity parameter values ​​among the n outdoor unit units. For example, if the capacity parameters of ODU1, ODU2, ODU3, and ODU4 increase sequentially, ODU1 and ODU2 will be configured as m first outdoor unit units, and ODU3 and ODU4 will be configured as k second outdoor unit units. Also, for example, if the capacity parameters of ODU1, ODU2, ODU3, and ODU4 decrease sequentially, ODU3 and ODU4 will be configured as m first outdoor unit units, and ODU1 and ODU2 will be configured as k second outdoor unit units.

[0063] Specifically, as shown in Figure 8, if n is equal to 2, the defrosting priority of ODU1 and ODU2 can be determined based on the flow in Figure 9 or Figure 10. As shown in Figure 12, if n is equal to 3, the defrosting priority of ODU1 and ODU2 can be determined based on the flow in Figure 13. As shown in Figure 14, if n is equal to 4, the defrosting priority of ODU1 and ODU2 can be determined based on the flow in Figure 14.

[0064] Figure 8 is a schematic diagram of the refrigerant flow in the defrosting process of ODU1 based on ODU2 when n is equal to 2. In this case, ODU2 is in heating mode and ODU1 is in defrosting mode.

[0065] Figure 12 is a flowchart of the defrosting of ODU1 based on ODU2 and ODU3 when n is equal to 3. In this case, ODU2 and ODU3 are in heating mode, and ODU1 is in defrosting mode.

[0066] Figure 14 is a flowchart of defrosting ODU1 and ODU2 based on ODU3 and ODU4 when n is equal to 4. In this case, ODU3 and ODU4 are in heating mode, and ODU1 and ODU2 are in defrosting mode.

[0067] Refer to Figure 16. Figure 16 is a flowchart of a control method for an air conditioning heat pump system provided by an embodiment of the present application. The air conditioning heat pump system includes an indoor unit and n outdoor unit units, where n is an integer greater than 1. The control method includes, when the air conditioning heat pump system is in alternating defrost mode, step 1601 acquiring capacity parameters of the n outdoor unit units; step 1602 dividing the n outdoor unit units into m (where m is an integer greater than 0) first outdoor unit units and k (where k is an integer greater than 0, and the sum of m and k is n) second outdoor unit units, the sum of which is less than or equal to the sum of which is the capacity parameters of the m first outdoor unit units; step 1603 controlling the m first outdoor unit units to operate in heating mode and the k second outdoor unit units to operate in defrost mode; and step 1604 controlling the m first outdoor unit units to operate in defrost mode and the k second outdoor unit units to operate in heating mode after the defrosting of the k second outdoor unit units is completed.

[0068] This embodiment provides a control method for an air conditioning heat pump system when the evaporation capacity parameter is a capacity parameter, and its specific implementation process is the same as in the above embodiment, and it can implement all the processes in the above embodiment, and moreover, it has all the beneficial effects of the above embodiment.

[0069] Refer to Figure 17. Figure 17 is a flowchart of a control method for an air conditioning heat pump system provided by an embodiment of the present application. The air conditioning heat pump system includes an indoor unit and n outdoor unit units, where n is an integer greater than 1. The control method includes, when the air conditioning heat pump system is in alternating defrosting mode, step 1701: obtaining the frost thickness values ​​of the n outdoor unit units; step 1702: dividing the n outdoor unit units into m (where m is an integer greater than 0) first outdoor unit units and k (where k is an integer greater than 0, and the sum of m and K is n) second outdoor unit units, the sum of which is greater than or equal to the sum of which is the frost thickness values ​​of the m first outdoor unit units; step 1703: controlling the m first outdoor unit units to operate in heating mode and the k second outdoor unit units to operate in defrosting mode; and step 1704: after defrosting of the k second outdoor unit units is completed, controlling the m first outdoor unit units to operate in defrosting mode and the k second outdoor unit units to operate in heating mode.

[0070] This embodiment provides a control method for an air conditioning heat pump system when the evaporation capacity parameter is the frost thickness value, and its specific implementation process is the same as in the above embodiment, and it can implement all the processes in the above embodiment, and moreover, it has all the beneficial effects of the above embodiment.

[0071] Refer to Figure 18. Figure 18 is a flowchart of a control method for an air conditioning heat pump system provided by an embodiment of the present invention. The air conditioning heat pump system includes an indoor unit and n outdoor unit units, where n is an integer greater than 1. The control method includes, when the air conditioning heat pump system is in alternating defrosting mode, step 1801 determining whether each of the n outdoor units satisfies the defrosting conditions; step 1802 dividing the n outdoor units into m (where m is an integer greater than 0) first outdoor units that satisfy the defrosting conditions and k (where k is an integer greater than 0, and the sum of m and k is n) second outdoor units that do not satisfy the defrosting conditions; step 1803 controlling the m first outdoor units to operate in heating mode and the k second outdoor units to operate in defrosting mode; and step 1804 controlling the m first outdoor units to operate in defrosting mode and the k second outdoor units to operate in heating mode after defrosting of the k second outdoor units is completed.

[0072] In related technologies, it is generally determined that an outdoor unit satisfies the defrosting conditions if the thickness of the frost layer on the outdoor unit is above a certain threshold, and that the outdoor unit does not satisfy the defrosting conditions if the thickness of the frost layer on the outdoor unit is below the aforementioned threshold. Therefore, by setting the evaporation capacity parameter of an outdoor unit that satisfies the defrosting conditions to 1 and the evaporation capacity parameter of an outdoor unit that does not satisfy the defrosting conditions to 0, the evaporation capacity parameter can be determined according to whether or not the outdoor unit satisfies the defrosting conditions.

[0073] In some embodiments of the present invention, the air conditioning heat pump system includes two outdoor unit units, ODU1 and ODU2. In alternating defrosting mode, the evaporation capacity parameters of ODU1 and ODU2 are obtained depending on whether the defrosting conditions are met. If the evaporation capacity parameter of ODU1 is 0 and the evaporation capacity parameter of ODU2 is 1, ODU1 is defrosted first, and after the defrosting of ODU1 is completed, ODU2 is defrosted.

[0074] In another embodiment of the present invention, the air conditioning heat pump system includes four outdoor unit units ODU1, ODU2, ODU3, and ODU4. In alternating defrosting mode, the evaporation capacity parameters of ODU1, ODU2, ODU3, and ODU4 are obtained depending on whether the defrosting conditions are met. If the evaporation capacity parameters of ODU1 and ODU2 are both 0, and the evaporation capacity parameters of ODU3 and ODU4 are both 1, ODU1 and ODU2 are defrosted first, and after the defrosting of ODU1 and ODU2 is completed, ODU3 and ODU4 are defrosted further.

[0075] This embodiment is a control method for an air conditioning heat pump system corresponding to the embodiment in which evaporation capacity parameters are determined depending on whether or not the outdoor unit unit satisfies defrosting conditions, and its specific implementation process is the same as that of the embodiment, and it can implement all the processes in the embodiment and has all the beneficial effects of the embodiment.

[0076] Refer to Figure 2. Figure 2 is a schematic diagram of the configuration of an air conditioning heat pump system provided by an embodiment of the present application. The air conditioning heat pump system includes a controller, an indoor unit, a first transmission line, a second transmission line, and n (n is an integer greater than 1) outdoor unit units, the indoor unit and the n outdoor unit units are each electrically connected to the controller. Each outdoor unit includes a storage tank, a compressor, a heat exchanger, a first four-way valve, a second four-way valve, an electronic expansion valve, a first line, and a second line, and in each outdoor unit, the output end of the storage tank and the input end of the compressor are connected via a line, the output end of the compressor and the E end of the first four-way valve are connected via a line, the D end of the first four-way valve and the D end of the second four-way valve are connected via a line, and the C end of the second four-way valve and the input end of the heat exchanger are connected via a line. The output end of the heat exchanger is connected to the first end of the first conduit, the electronic expansion valve is provided in the first conduit, the second end of the first conduit forms the first external port of the outdoor unit, the S end of the second four-way valve and the C end of the first four-way valve are connected via a conduit, the S end of the first four-way valve and the input end of the storage tank are connected via a conduit, the E end of the second four-way valve is connected to the first end of the second conduit, and the second end of the second conduit forms the second external port of the outdoor unit. The first transmission conduit includes one input end connected to the output end of the indoor unit and n first connection ends connected in one-to-one correspondence to the n first external ports of the n outdoor unit units. The second transmission conduit includes one output end connected to the input end of the indoor unit and n second connection ends connected in one-to-one correspondence to the n second external ports of the n outdoor unit units.

[0077] As a selectable embodiment, the controller, when m of the n outdoor units are in heating mode and k of the n outdoor units are in defrosting mode, causes the D and E ends of the first four-way valve in the first outdoor unit to conduct, the S and C ends of the first four-way valve in the first outdoor unit to conduct, and the D and E ends of the second four-way valve in the first outdoor unit to conduct, and the first outdoor unit The system is controlled such that the S and C ends of the second four-way valve in the unit are conductive, the D and C ends of the first four-way valve in the second outdoor unit are conductive, the S and E ends of the first four-way valve in the first outdoor unit are conductive, the D and C ends of the second four-way valve in the second outdoor unit are conductive, and the S and E ends of the second four-way valve in the second outdoor unit are conductive, where m and k are integers greater than 0, and the sum of m and k is n. The controller controls the first four-way valve in the first outdoor unit to conduct electricity when m of the n first outdoor unit units are in defrost mode and k of the n second outdoor unit units are in heating mode, so that the D and C ends of the first four-way valve in the first outdoor unit conduct electricity, the S and E ends of the first four-way valve in the first outdoor unit conduct electricity, the D and C ends of the second four-way valve in the first outdoor unit conduct electricity, the S and E ends of the second four-way valve in the first outdoor unit conduct electricity, the D and E ends of the first four-way valve in the second outdoor unit conduct electricity, the S and C ends of the first four-way valve in the first outdoor unit conduct electricity, the D and E ends of the second four-way valve in the second outdoor unit conduct electricity, and the S and C ends of the second four-way valve in the second outdoor unit conduct electricity.

[0078] The air conditioning heat pump system provided by this embodiment is an air conditioning heat pump system corresponding to the embodiment described above, and the controller in the air conditioning heat pump system can implement each process of the control method in the embodiment described above, has similar beneficial effects, and will not be described further here to avoid duplication.

[0079] Although embodiments of the present application have been described above based on the attached drawings, the present application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not limiting. A person skilled in the art can take many forms that fall within the scope of protection of the present application without departing from the spirit and scope protected by the claims of the present application, under the disclosure of the present application.

Claims

1. In a control method for an air conditioning heat pump system, The aforementioned air conditioning heat pump system includes an indoor unit and n (where n is an integer greater than 1) outdoor unit units. The control method described above is When the air conditioning heat pump system is in alternating defrost mode, evaporation capacity information for the n outdoor unit is obtained, which includes an evaporation capacity parameter used to represent the evaporation capacity during the operation process of the corresponding outdoor unit, and which includes n evaporation capacity parameters that correspond one-to-one to the n outdoor unit. Based on the evaporation capacity information, the n outdoor unit units are divided into m (where m is an integer greater than 0) first outdoor unit units and k (where k is an integer greater than 0, and the sum of m and k is n) second outdoor unit units, the sum of which of the evaporation capacity parameters is less than or equal to the sum of the evaporation capacity parameters of the m first outdoor unit units. The m first outdoor unit units are controlled to operate in heating mode, and the k second outdoor unit units are controlled to operate in defrosting mode. After the defrosting of the k second outdoor units is completed, the m first outdoor units are controlled to operate in defrost mode, and the k second outdoor units are controlled to operate in heating mode. The aforementioned evaporation capacity parameter is determined based on the capacity parameter of the outdoor unit, the frost thickness value of the outdoor unit, or whether the outdoor unit meets the defrosting conditions. Here, the evaporation capacity parameter and the capacity parameter show a positive correlation, and the evaporation capacity parameter and the frost thickness value show a negative correlation. A control method characterized in that the frost thickness value and the power ratio of the outdoor unit, which is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, show a positive correlation.

2. In the control method described in claim 1, Each of the first outdoor unit units includes one first compressor and one first heat exchanger. Each of the second outdoor unit units includes one second compressor and one second heat exchanger. When the m first outdoor units operate in heating mode and the k second outdoor units operate in defrosting mode, the first compressor is in operation, the second compressor is in non-operational state, the heat exchanger in the first outdoor unit forms an evaporator in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms a condenser in the air conditioning heat pump system, and in any of the second outdoor units, the input terminal of the second heat exchanger communicates with the output terminal of each first compressor, and the output terminal of the second heat exchanger communicates with the input terminal of each first compressor. A control method characterized in that, when the m first outdoor units operate in defrost mode and the k second outdoor units operate in heating mode, the first compressor is in a non-operating state and the second compressor is in an operating state, the heat exchanger in the first outdoor unit forms a condenser in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms an evaporator in the air conditioning heat pump system, and in any of the first outdoor units, the input terminal of the first heat exchanger communicates with the output terminal of each second compressor, and the output terminal of the first heat exchanger communicates with the input terminal of each second compressor.

3. In the control method described in claim 1, Each of the first outdoor unit units includes one first compressor and one first heat exchanger. Each of the second outdoor unit units includes one second compressor and one second heat exchanger. When the m first outdoor units operate in heating mode and the k second outdoor units operate in defrosting mode, the first compressor is in operation, the second compressor is in operation, the heat exchanger in the first outdoor unit forms an evaporator in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms a condenser in the air conditioning heat pump system, and in any of the second outdoor units, the input terminal of the second compressor communicates with the output terminal of each first compressor, the output terminal of the second compressor communicates with the input terminal of the second heat exchanger, and the output terminal of the second heat exchanger communicates with the input terminal of each first compressor. A control method characterized in that, when the m first outdoor units operate in defrost mode and the k second outdoor units operate in heating mode, the first compressor is in operation, the second compressor is in operation, the heat exchanger in the first outdoor unit forms a condenser in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms an evaporator in the air conditioning heat pump system, and in any of the first outdoor units, the input terminal of the first compressor communicates with the output terminal of each second compressor, the output terminal of the first compressor communicates with the input terminal of the first heat exchanger, and the output terminal of the first heat exchanger communicates with the input terminal of each second compressor.

4. In the control method described in claim 3, When the m first outdoor unit units operate in heating mode and the k second outdoor unit units operate in defrosting mode, further, This includes controlling the frequency of the first compressor based on the exhaust pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor, When the m first outdoor unit units operate in defrost mode and the k second outdoor unit units operate in heating mode, further, A control method characterized by including controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the exhaust pressure of the second compressor.

5. In the control method described in claim 4, Controlling the frequency of the first compressor based on the exhaust pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor is, When the exhaust pressure of the first compressor is equal to or greater than a first threshold, the frequency of the first compressor is controlled to decrease, and when the exhaust pressure of the first compressor is less than the first threshold, the frequency of the first compressor is controlled to increase. The method includes setting the frequency of the second compressor to a first frequency value which is a times the frequency of the first compressor if the compression ratio of the second compressor is equal to or greater than a second threshold, and setting the frequency of the second compressor to a second frequency value which is b (b > a) times the frequency of the first compressor if the compression ratio of the second compressor is less than the second threshold. Controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the exhaust pressure of the second compressor is, If the compression ratio of the first compressor is greater than or equal to the second threshold, the frequency of the first compressor is set to a third frequency value which is a times the frequency of the second compressor; if the compression ratio of the first compressor is less than the second threshold, the frequency of the first compressor is set to a fourth frequency value which is b times the frequency of the second compressor. A control method characterized by including controlling the frequency of the second compressor to decrease when the exhaust pressure of the second compressor is equal to or greater than the first threshold, and controlling the frequency of the second compressor to increase when the exhaust pressure of the second compressor is less than the first threshold.

6. In the control method described in claim 1, When the air conditioning heat pump system is in alternating defrost mode, before acquiring the evaporation capacity information of the n outdoor unit units, A power ratio which is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, wherein the power ratio of each of the n outdoor units is obtained to obtain n power ratios, If at least one of the n power ratios is greater than or equal to a third threshold, the air conditioning heat pump system is controlled to switch to a normal defrosting mode in which the heat exchangers in the n outdoor units form condensers and the heat exchangers in the indoor units form evaporators. A control method characterized by including controlling the air conditioning heat pump system to switch to the alternating defrosting mode if all of the n power ratios are below the third threshold.

7. In the control method described in claim 1, When n is equal to 2, the m first outdoor unit includes the one outdoor unit with the largest evaporation capacity parameter value among the n outdoor unit units, and the k second outdoor unit includes the one outdoor unit with the smallest evaporation capacity parameter value among the n outdoor unit units. A control method characterized in that, when n is equal to 4, the m first outdoor unit units include the two outdoor unit units with larger evaporation capacity parameter values ​​among the n outdoor unit units, and the k second outdoor unit units include the two outdoor unit units with smaller evaporation capacity parameter values ​​among the n outdoor unit units.

8. In a control method for an air conditioning heat pump system, The aforementioned air conditioning heat pump system includes an indoor unit and n (where n is an integer greater than 1) outdoor unit units. The control method described above is When the air conditioning heat pump system is in alternating defrost mode, the capacity parameters of the n outdoor unit units are obtained, Based on the capacity parameters, the n outdoor unit units are divided into m (where m is an integer greater than 0) first outdoor unit units and k (where k is an integer greater than 0, and the sum of m and k is n) second outdoor unit units, the sum of which is less than or equal to the sum of the capacity parameters of the m first outdoor unit units. The m first outdoor unit units are controlled to operate in heating mode, and the k second outdoor unit units are controlled to operate in defrosting mode. A control method characterized by including, after the defrosting of the k second outdoor units is completed, controlling the m first outdoor units to operate in defrost mode and controlling the k second outdoor units to operate in heating mode.

9. In a control method for an air conditioning heat pump system, The aforementioned air conditioning heat pump system includes an indoor unit and n (where n is an integer greater than 1) outdoor unit units. The control method described above is When the air conditioning heat pump system is in alternating defrost mode, the frost thickness values ​​of the n outdoor unit units are obtained, Based on the frost thickness values, the n outdoor unit units are divided into m (where m is an integer greater than 0) first outdoor unit units and k (where k is an integer greater than 0, and the sum of m and k is n) second outdoor unit units, the sum of which is greater than or equal to the sum of the frost thickness values ​​of the m first outdoor unit units. The m first outdoor unit units are controlled to operate in heating mode, and the k second outdoor unit units are controlled to operate in defrosting mode. After the defrosting of the k second outdoor units is completed, the m first outdoor units are controlled to operate in defrost mode, and the k second outdoor units are controlled to operate in heating mode. A control method characterized in that the frost thickness value and the power ratio of the outdoor unit, which is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, show a positive correlation.

Images